In a large saucepan, bring water and butter to a boil. Add flour all at
once, stirring until a smooth ball forms. Remove from heat; let stand 5 minutes.
Add eggs, one at a time, beating well after each addition. Continue beating
until mixture is smooth.
Line baking sheet with parchment paper. Brush water over parchment paper.
Fill piping bags with pastry dough and pipe circle swirls 3 inches apart.
Bake 30-35 minutes or until golden brown. Remove to wire racks.
For filling, in a small heavy saucepan, combine beaten egg, sugar, lemon
juice and butter. Slowly cook and stir over medium heat until mixture is thick
enough to coat the back of a spoon. Transfer to a small bowl; refrigerate until
partially set. Whisk again to make sure ingredients are mixed well.
In a large bowl, beat whipped cream and sugar until stiff peaks form; fold
in lemon mixture.
Fill pastry bag with lemon filling. Split pastry puffs. Pipe lemon filling
onto pastry bottoms, replace pastry tops. Dust with powdered sugar.
Watch the video below on how to make Lemon Cream Puffs.